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point of reception. This eliminates the subsequent
processing of packets that will just be dropped by the
destination port.
VLANs in Layer 2 Only Mode
The switch initially configures one VLAN, VID = 1, called the
DEFAULT_VLAN. The factory default setting assigns all
ports on the switch to the DEFAULT_VLAN.
Packets cannot cross VLANs if the switch is in Layer 2 Only
mode. If a member of one VLAN wants to connect to
another VLAN, the link must be through an external router.
When the switch is in Layer 2 Only mode, 802.1Q VLANs
are supported.
If no VLANs are configured on the switch and the switch is in
Layer 2 Only mode, then all packets will be forwarded to
any destination port. Packets with unknown source
addresses will be flooded to all ports. Broadcast and
multicast packets will also be flooded to all ports.
A VLAN that does not have a corresponding IP interface
defined for it, will function as a Layer 2 Only VLAN –
regardless of the Switch Operation mode.
Layer 3-Based VLANs
Layer 3-based VLANs use network-layer addresses (subnet
address for TCP/IP) to determine VLAN membership. These
VLANs are based on layer 3 information, but this does not
constitute a 'routing' function.
The VH-2402-L3 allows an IP subnet to be configured for
each 802.1Q VLAN that exists on the switch.
Even though a switch inspects a packet's IP address to
determine VLAN membership, no route calculation is
performed, the RIP protocol is not employed, and packets
traversing the switch are bridged using the Spanning Tree
algorithm.
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VH-2402-L3 Management Guide 135
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